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SMART-1 SPICE KERNELS SET

ESA, in collaboration with NAIF and the SMART-1 Instrument Teams, produce a whole set of SPICE kernels for SMART-1 (event kernels are not produced for ESA missions). Refer to the description of the SMART-1 repository for information about naming conventions and time coverage for each of the kernels.

The SMART-1 SPICE dataset consists of several SPICE kernels, organised as follows:

CK kernels: This kernels contain information about orientation of the space vehicle or any articulating structure on it.

FK kernels: Reference frame specifications. Definitions of, and specifications of, relationships between reference frames (coordinate systems). Among the frames kernels included, there are kernels that specify reference frames related to the earth and the spacecraft.

IK kernels: Kernels that hold intrument information, such as field of view or internal timing.

LSK kernel: This kernels hold a table with the leapseconds used to convert between ET and UTC.

PCK kernels: These kernels provide information about Solar System bodies orientation and shape, and possibly parameters for gravitational, atmospheric or rings models.

SCLK kernel: This kernel (spacecraft clock coefficients) allows for conversion between ET and spacecraft clock. If there are multiple LSK kernels in this dataset, the latest kernel supersedes he previous ones. More information on the SCLK kernel(s) in this dataset is provided in SCLKINFO.TXT.

SPK kernels: Kernels with information about ephemeris (position and velocity) of the spacecraft and solar system bodies. The dataset provides such information for the planets, the Sun, the Moon, the New Norcia tracking station, several DSN tracking stations, and the spacecraft. More information on the SPK kernels in this dataset is provided in SPKINFO.TXT.

ACCESS TO THE KERNELS

ORIGIN OF THE KERNELS

NAIF generates kernels that are mission independent. Some of them are used by ESA missions:

Binary and text PCK and LSK kernels.

Some SPK kernels with ephemeris of the solar system bodies.

SPK kernels for ground stations.

Frames kernels for ground stations.

Other Kernels provided by NAIF

NAIF collaborates with the ESA SPICE Team and the Intrument Teams to create instrument and frames kernels for the different ESA Missions:

The instrument kernels (IK) have been developed NAIF, the intrument teams and RSSD/ESA.

The SMART-1 frames kernel has been created by NAIF, in collaboration with RSSD/ESA.

Kernels Generated with ESOC anillary data

Orbit, clock and attitude kernels are created from ESOC data:

ESOC ancillary data are the main source of information required to create SPICE kernels for attitude (CK), orbit (SPK) and time (SCLK) information for the Spacecraft.

KERNELS CREATED BY THE ESA SPICE SERVICE

These include:

CK kernels with orientation of the SMART-1 Solar Arrays.

RSSD frames kernel.

Creation of SPK, CK and SCLK kernels from ESOC Ancyllary data

Orbit Data

In terms of orbital data, the mission can be divided in two different phases: cruise and nominal. The ftp repository provides the most up to date orbit kernels for SMART-1.

Several different types of data products are provided by ESOC: ORES and ORMS. The ORES product covers the cruise phase from launch to the Moon Insertion, and provides the orbit data as earth-centric states. There is only one ORES product. During the nominal phase, new ORMS files were provided on a regular basis. The orbital data contained in these files provide the state of SMART-1 with respect to the Moon.

Attitude Data

Attitude data for the spacecraft were provided for all mission phases except for safe modes, for the past and the near future. The attitude is provided in several records, called segments, each covering a specific time span. These segments have no overlap, but there may be gaps between the segments, and even gaps in the segments. The available attitude data is usually predicted, although kernels with reconstructed data are present (for time intervals for which the predicted attitude is known to be not accurate enough).

Time Correlation Data

Time Correlation is one of the most critical pieces of information needed for the use of the SPICE system within the SMART-1 mission. This information allows the conversion between the SMART-1 S/C Clock time and UTC time. ESOC delivered time correlation data which are the source for the SCLK kernel.

An automated system, called ADCS (Automatic Data Conversion System) is responsible for the generation of CK, SPK and SCLK kernels from the ESOC flight dynamics data. ADCS detects when a new product was generated or a new time correlation packet is available, and run a series of processes in order to create the corresponding kernels.

ADCS uses the SPICE toolkit in order to fulfill its task. It runs in a server physically located at ESAC.